Save or Die could take effect when and character or monsters is bloodied.
The only issue is that it makes Bloodied a very dangerous condition to be in.
Or leads to a lot more restingAnd subsequently lead to demands that the healer take care of every last nick, scratch, and booboo immediately.
I dislike the proposed method in the blog, btw. I think it forces you to have to guess the oppositions current HP state, which renders such powers fairly useless for PC but less so for the DM causing a weirdly imbalanced situation, or it forces too much transparency which highlights the mechanics and the gamey nature of things, and would undoubtedly be a problem for a great number of people.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.